Measurement of trigonal sensitivity as a test of bladder function.

A method has been developed for the measurement of sensory receptors that respond to pressure at the base of the bladder and posterior urethra. The application of force to a balloon catheter placed at that part of the bladder regularly results in an urge to urinate. People with normal voiding perceive the urge to void when 245 +/- 47 gm. (standard deviation) of force are applied. Patients with irritative symptoms (urinary frequency and urgency) perceive the urge to void when 132 +/- 50 gm. (p equals 0.0003) are applied. After enucleative prostatectomy more force is required to cause the urge to void (344 +/- 48 gm., p equals 0.0003) and even more force is required after radical prostatectomy (469 +/- 54 gm., p equals 0.0002). Patients with acute urinary retention or urinary stress incontinence were not distinguishable from the normal group. Patients with chronic urinary retention may be divided into 2 subgroups: 1 with normal sensory perception and 1 with reduced perception (526 +/- 32 gm., p equals 1.6 X 10(-9)). Three patients with urinary urgency not associated with frequency did not perceive the urge to void until 541 +/- 21 gm. (p equals 6.2 X 10(-7)) had been applied. Some elderly patients could not reproducibly report the urge to void. When lidocaine was applied topically within the bladder sensitivity was reduced by 210 +/- 114 gm. (p equals 0.003). It is suggested that pressure sensitive receptors in the mucosa or submucosa of the bladder base and posterior urethra have a role in micturition, that their activity can be quantitated and that protocols designed to manage them may have impact on the care of patients with voiding disorders.